1. Field of the Invention
The present invention relates to a sport boot in which the functions of tightening and protecting the foot are performed by implementing a tightening device cooperating with at least one movable flap found outside the upper and adapted to be pressed against the latter.
2. Background and Material Information
Known sport boots of this type, such as those described in the patents GB 363 008, FR 569 694, FR 2 694 167, and GB 1 545 475, have an upper that is generally provided with a front longitudinal opening on the top, and they can be adjusted on the foot by bringing the edges of the opening, i.e., the flanks of the upper, closer together by means of a tightening device capable of using at least one movable flap. As taught, the movable flap or flaps extend freely on the corresponding flanks of the upper, from an attachment zone remote from the front longitudinal opening, and located at the level of the sole of the boot. Due to these various arrangements, when a movable flap is tightened, the latter is pressed against the corresponding flank of the upper and thus biases it to become narrower in the direction of the foot, which thus results in the edges of the front longitudinal opening of the upper being brought closer together. Likewise, because of this same tightening action on a movable flap, the wall of the boot is provided with a double thickness in the flap area, because it is constituted by the wall of the flank of the upper and by that of the flap which overlap one another. The wall of the boot thus has, in the location of each movable flap, an increased resistance that notably improves the protection of the foot from the outside, especially against shocks.
Furthermore, the use of a movable flap also makes it possible to distribute a substantial portion of the tightening stresses on the latter, selectively along the zone of the upper where it extends, instead of essentially and totally on the upper, as is the case with conventional boots where the lacing exerts a direct pulling action on the latter. Indeed, these boots having at least one movable flap make it possible to ensure a proper protection as well as a tightening of the foot without direct pulling action on the upper in the location of the movable flap or flaps, since it is the latter that are secured to the tightening device. However, they have certain disadvantages related in particular to the proportioning of the tightening force on the foot and to problems of quick wear and tear and deterioration. Indeed, in this type of boots, the frictions and deformations that occur between the wall of the upper and/or the movable flap or flaps absorb a portion of the tightening force restituted by the upper on the foot.
This disadvantage is especially more sensitive as at least one of either the upper or the flap is made out of a material having a strong modulus, such as leather, as is generally the case. Furthermore, because the movable flaps of these boots are located in an excessive thickness on the wall of the flank of the upper, they constitute projecting portions that are exposed to external elements and actions, and can get caught, be torn, or even stripped, therefore likely to be prematurely worn out with respect to the boot considered in its entirety.